Photomultiplier (photomultiplier tube or PMT) is a very versatile and sensitive detector of radiant energy in the ultraviolet, visible, and near infrared regions of the electromagnetic spectrum. A typical photomultiplier tube consists of a photoemissive cathode (photocathode) followed by focusing electrodes, an electron multiplier (dynode) and an electron collector (anode) in a vacuum tube.
Rubidium was discovered by Robert Bunsen and Gustav Kirchhoff (Germany) in 1861. The origin of the name comes from the Latin word rubidius meaning dark red or deepest red. It is soft, silvery-white, highly reactive metal. Ignites in air. Reacts violently with water or oxidants. Rubidium occurs abundantly, but so widespread that production is limited. Usually obtained from lithium production. Used as a catalyst, photocells and vacuum and cathode-ray tubes.
Evangelista Torricelli (1852-1908) is Italian physicist and mathematician. He became the first scientist to create a sustained vacuum and to discover the principle of a barometer. He filled a tube three feet long, and hermetically closed at one end, with mercury and set it vertically with the open end in a basin of mercury, taking care that no air-bubbles should get into the tube. The column of mercury invariably fell to about twenty-eight inches, leaving an empty space above its level. He discovered that the variation of the height of the mercury from day to day was caused by changes in the atmospheric pressure. He also constructed a number of large objectives and small, short focus, simple microscopes.
Tungsten was discovered by Fausto and Juan Jose de Elhuyar (Spain) in 1783. Named after the tungsten mineral wolframite. It is hard, steel-grey to white metal. Highest melting point of all metals. Resists oxygen, acids and alkalis. Tungsten occurs in the minerals scheelite (CaWO4) and wolframite [(Fe,Mn)WO4]. Made into filaments for vacuum tubes and electric lights. Also as contact points in cars. Tungsten carbide is extremely hard and is used for making cutting tools and abrasives.
Generalic, Eni. "Vacuum filtration,1713711111." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
Glossary
Periodic Table
